Java

Example: Hash Text in Chunks

Shows how to generate a final hash, like SHA-256, for a large text by processing it in chunks. Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.Crypt2;

public class ChilkatExample {

    public static void main(String[] args) {
        Crypt2 crypt = new Crypt2();
        crypt.setHashAlgorithm("sha256");
        crypt.setCharset("utf-8");

        BinData bd = new BinData();

        String s = "The quick brown fox jumped over the lazy dog.\r\n";

        // Accumulate the text in a StringBuilder.  We'll demonstrate hashing the text in chunks,
        // and then also hashing the entire text at once to show the results are the same.

        bd.appendString(s, "utf-8");
        crypt.hashBeginString(s);

        int i = 0;
        while (i < 200) {
            bd.appendString(s, "utf-8");
            crypt.hashMoreString(s);
            i = i + 1;
        }

        // Get the hash in base64 format.
        crypt.setEncodingMode("base64");

        String encodedHash = crypt.hashFinalENC();
        System.out.println("Hash computed in chunks: " + encodedHash);

        // Let's alternatively compute the hash of the entire amount of data at once,
        // to show the hash computation is the same:
        encodedHash = crypt.hashBdENC(bd);
        System.out.println("Hash computed in 1 step: " + encodedHash);

        // Output:

        // Hash computed in chunks: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
        // Hash computed in 1 step: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
    }
}